Core Viewpoint - The article discusses a specific algorithm problem from LeetCode, focusing on the "132 pattern" in an integer array, and provides a detailed explanation of how to solve it using a monotonic stack approach [4][9]. Summary by Sections Algorithm Problem Description - The problem is to determine if there exists a subsequence in the array that follows the "132 pattern," where for three integers nums[i], nums[j], and nums[k], the conditions i < j < k and nums[i] < nums[k] < nums[j] must hold true [5][9]. Examples - Example 1: For the input nums = [1,2,3,4], the output is false, indicating no "132 pattern" exists [6]. - Example 2: For the input nums = [3,1,4,2], the output is true, as the subsequence [1, 4, 2] satisfies the "132 pattern" [8]. Problem Analysis - The solution involves using a monotonic stack to efficiently find the "132 pattern." An auxiliary array, leftMin, is used to track the minimum values to the left of each element [9][10]. Implementation Details - The algorithm iterates from the end of the array to the beginning, checking for the "3" in the "132 pattern" and using the stack to find the corresponding "2" and "1" [10][12]. - The Java and C++ implementations of the algorithm are provided, demonstrating how to set up the leftMin array and the stack operations [10][13].